High-speed self-laying track vehicle



Feb. 21, 1928.

W. H. SMYTH HIGH SPEED SELF LAYING- TRACK VEHICLE Filed July 28, 1925 2 Sheets-Sheet l INVENTOR INVENTQ'R 9 QAQE a w. H. SMY'I 'H HIGH SPEED SELF LAYING TRACK VEHICLE Feb. 21, 1928.

llllllll|lflllllllll (liillli ll. (4! III I v mag Patented Feb. 21, 1928.

WILLIAM H. SMYTH, 0F BERKELEY, CALIFORNIA.

HIGH-SPEED SELF-LAYING TRACK VEHICLE.

Application fl ed July 28,

This invention relates to the class of vehicles that lay down a supporting track as, and upon which, they travel. It has for'its main object to notably increase the'capability for speed and traction in this type of yehicle. Incidental to themain purpose, another object is to reduce the number of actively load-bearing parts in the wheelbase while increasing its effective length and. responsiveness to changes in the ground surface contour and load conditions; also to cushion the machine under these varying conditions and especially to eliminate the destructive jars incident to track-chain joint-buckling and the sharp kinking of the chain-hinge joints in passing over localized resistantobstructions. Still another object is to so, construct the device that the parts shall be adaptedto large-scale'manufacture and easy to assemble, to dismemberor to replace worn parts.

A typical expression of my invention that accomplishes these objects is shown in-the accompanying drawings wherein:

Fig. 1 shows a side elevation, parts being removed for better illustration;

Fig. 2 shows a side elevation of a partial assemblage illustrating modification in some details of construction;

Fig. 3 showsa transverse section of' the form illustrated in Fig. 2, on the dotted line Fig. 4 shows a plan View, parts being broken away for better illustration;

Fig. 5 shows a detail of construction, on a somewhat enlarged scale.

As the track-assembly alone distinguishes the self-laying-track type from the round-' wheeler form of vehicle, the other parts 'be- 1923. Serial No. 654,432.

work pertaining to a self-laying-track ve-' hicle. It carries journal-box B, shaft C, and power-wheel D.

.E E is a curved guide-rai1 preferably formed of an upper and a lower rail hinged together and to the frame at E from which point the members E and E curve upward and downward respectively and rearwardly into proximity to the periphery of wheel D, with which the rail members constitute a substantially continuous flexibly-hinged and resilient guide-way for an endless track- 'chain, thus providing means to maintain the upper and lower folds of the chain in the same plane of travel; 7 f The upper member of the curved guide- ,rail may beprovided with a flexible extenbility and resilience.

I In Figs. 2 and 3, the second resilient section marked'e is shown as formed of stock channel iron. The lower rail member E may also have secured thereto, angle-iron .lateral extensions projecting over the tracks substantially the full width of the unoccupled space betweenthe frame members to form dirt-excluding rail-covers, as shown in section at 6 The flexibly-hinged rail-member E may a'lsobe provided with lateral abutments e contacting the frame members and vertically movable with reference there-- to, to prevent lateral displacement of the track in its groundrun.

F, is a load-bearing track-chain of ordinary const-ruction, other than that it is provided with antifriction rollers F journalled thereon below its track surface. The chaintrack is preferably twin-track, being made up of laterally adjacent parallel tracks f-f attached to suitable ground-bearing, treadplates F. The track-chain F, is trained about the guide-way formed by the guiderails EE and powerwheel, D, around which guide-way the chain travels on its antifriction rollers F in the manner indicated in the various views.

(it-G are truck" wheels,

preferably 7 flanged, travelable upon the groundrun of the track-chain F. These wheels constitute the sole support of the machine. They are shown formed as twin wheels G-G, G G to coactwith the twin-track f/, Fig. 4:- The twin members of the support Wheels Grand G are concentric, each pair on an axle g and each axle is-journalled in a suitable box or bearing 9 H-H are bracketarms, one of which is secured to each of the journal-boxes g and extends downwardly to the lower guide-rail section 6 to which it is pivotally connected, as shown in Fig. 1, thus forming a two-point support independently movable truck wheel-base.

I is a spring interposed between the journal-boxes 9 -9 and the frame of-the machine, to transfer-the load or weight of the motor parts resiliently to the support wheels G G In the present expression ofmy' invention, it is shown as a Y semi-elliptical spring with 'one ofits ends pivotally connected to one of the journal-boxes 9 at 2', its other end being similarly connected to the other journal-box.

To attach the spring I, to the frame of the machine, a "short beam A extends across the frame members, to which the beam is secured, and on the top of the beam the spring is strongly attached by a clamping plate a, and bolts a a Foradditional rigidity in the framework, the lower flange of the beam A may be bent downward at each of its ends to form lateral abutments to the frame members as shown at A Figs. 3 and 5, and a tie-rod a provided, extending from side to side through these members. When this tie-rod is employed the bolts (L -a may extend down thereto, as

shown at a in Fig. 2, and take thecform of eye-bolts anchored on the tie-rod a Tubular spacers a are then provided between the eye-bolts a a and also between them and the frame members.

Asa holding means which cannot jar loose,as threaded bolts and nuts are. apt to, and as a means that can also take up any slack consequent on racking strains to which these devices are necessarily subject in customary use, I have provided wedge-keys a a*, split longitudinally after the manner "of cotter pins, as shown in the detail Fig. 5.

Extending upward from the plate a, is a short hollow standard A exteriorly threaded. Telescoping in this standard is a rod or short bar 6, having a laterally extended head or circumferential flange '6 at its upper end, which head or flange abuts against the under gide of the guiderail member E, as shown in A is a nut-on the threaded standard A, in the form of a'cup or socket and provided withradial holes for the employment of a lever or turning bar.

J is a helical spring seated in the socket sition on the opposite side of the complete .machine, like the two pairs of wheels in an ordinary spring-mounted four-wheel vehicle.

Hitherto, under present practice and construction, in the endless chain-track type of vehicle, no two of the (longitudinally disposed) carrying wheels simultaneouslybear an equal proportion of the load. As the machine progresses on ground-of normally uneven contour and hardness, the load shifts from one bearing wheel to the next with a succession of shocks due to surface inequalities; and, in thus shifting from wheel to wheel the load is momentarily transferred to the track chain as an upthrust between the peripheries of the wheels. This meansthat the load constantly changes from relatively harmless pressure to destructivetorsion strains, and the hinges aresubjectedto'a quick succession of violent wrenches resulting in rapid deterioration ofthe track-chain. Under these conditionshigh speed of travel comparable to round wheel vehicles, is prac ti-cally impossible. I

In traveling over uneven ground also; the

tractive capability varies continuously, from maximum when the whole/wheel base has fairly even ground contact to minimumwhen passing over a hummock, Thus the effective wheel-base tractive area can have little or no calculable relation butonly a hitor-miss approximation of the machine.

In the operation of my invention the wheels GG support theload resting on frame, and due to the fact that there are buttwo, (the twin-wheels being. deemed a unit), the load is equally divided between G and G as in an ordinary spring-mounted four-wheel road wagon or a four wheel truck of a stationary track vehicle. No load, as such, comes to the pullin power on the antifrietion rollers F on the groundrun of the track-chain, but only such pressure as is sufficient to maintain the tractive ground-contact of the tread-shoes f between the peripheries ofv G G and even this pressure is cushioned resiliently bythe section 6 of the guide-rail.

Traveling over roughsurfaces the spring I, cushions the shock of meeting obstructions, while bridge rail 0 resiliently conforms to unevencontours and provides uni-' form tractive contact over the whole length of the wheel-base, at the same time the yielding of section e avoids shocks on the hingepins and relieves the chain track from racking strains of kinking at the hinges. other words, the ground-run of the traek chain, (on normally'variable surface), is a smoothly undulating track} instead of as heretofore, a succession ofangularities formed by the-upth'rust'of the links a tthein hinges.

The track-chain F, travels on its rollers F with-antifrictionsmoothness around the guide-rail E, engaging and leaving-the power wheel D, and also the idler curvature-of the guide rail at the front end without the customary-jar: 'lhetrack-chain F, is maintained at a uniform adjusted tension by the adjustable spring J, in coaction with the upper member E, of the guide-rail.

In the various ways above described, the devices of the present invention obviates and prevents the jars and strains which under ordinary practice and construction are permitted and are mechanically endurable only at the cost of speed, necessitating the slow speeds customary heretofore in the chaintrack type of vehicle. The present described construction provides a resilient two-point support extended wheel-base for the trackassembly withthe upward fiexure of the I track-chain resiliently controlled between the support points, a result never heretofore accomplished; and thus is attained a selflaying-track vehicle inherently capable of high speed.

In view of these pioneer departures from present accepted practice and construction,

I do not desire to be limited to the particular expressions of my invention used herein for illustrative purposes, nor to be limited in any other way than in accord with a liberal interpretation and the reasonable import of the claims which follow and i I claim:

1. A load-bearing track-assembly for vehicles comprising an endless chain-track its lower run adapted to ground support with means to maintain its upper and lower folds in the same plane of travel, a truck between the folds of the chain having load-bearing track-wheels travelable upon the ground run and spaced apart to form a two-point support wheel-base for the assembly, and guide means coacting with the ground run of the chain between the peripheries of the loadbearing track-wheels to control its upward flexure. v

2. In a track assembly for vehicles, an endless chain of tread shoes with tracks thereon raised above their inner surface, load-bearing wheels travelable upon the ground run of the rails and dirt excluding rail-cover means disposed above the trackrails and below a plane tangential to the upper arcs of the load-bearing wheels.

3. A load-bearing track-assembly for vehicles comprising an endless chain-track its lower run adapted to ground support with means to maintain its upper and lower folds in the same plane of travel, a truck movable independently of said means between the foldsof the chain: having load-bearing trackovh'eels travelab'le' upon the ground run= spaced apartto :form a two-point 'sups port wheel-base for the assembly, and, a guidewcoactingwith the ground run ofthe chainbetween the peripheries of? the bath bearing wheels to control its flexure.

4.1A1load-bearingtrack-assembly for ve- I hicles comprising an endless chain ztrack its lower-run adapted to ground 3 support with means to maintain its upper and lower folds in the same plane of travel, a truck between the folds of the chain having load-bearing spring-opposed track-wheels travelable upon the ground run spaced apart to form a twopoint support wheel-base for the assembly, and means coacting with the ground run of the chain between the peripheries of the load-bearing track-wheels'to control its flexure.

5. A load-bearing track-assembly for vehicles comprising an endless chain-track its lower run adapted to ground support with means to maintain its upper and lower folds in the same plane of travel, a truck between thejfolds of the chain having load-bearing track-wheels tra-velable upon the ground run spacedapart to form a two-point support 'wheel-base for the assembly, and resilient means coacting with the ground run between the peripheries of the load-bearing trackwheels' to resiliently control its upward flexure.

-6. A load-bearing track-assembly for vehicles comprising an endless chain-track with antifriction rollers journaled thereon its lower run adapted to ground support with means to maintain its upper and lower folds-in the same plane of travel, a truck between the folds of the chain having spring-opposed track wheels travelable upon the ground run spaced apart to form a twopoint support wheel-base for the assembly, and resilient means coacting with the antifriction rollers of the chain between the peripheries of the load-bearing track-wheels to control its upward fleXure.

7. Ina track-assembly for vehicles an endless chain-track, independently movable spring-pressed load-bearing wheels travelable upon the ground run of the chain spaced apart to form a two-point support wheelbase for the assembly, and resilient means to control the upward fiexure of the track between the points of support.

8. In a track-assembly for vehicles, an endless chain-track, a wheel near one end, an oppositely disposed curved member 00- acting with the'wheel to maintain the upper and lower folds of the chain-track in the same plane of travel, support-wheels travela-ble' upon the lower fold of the track intermediate of the wheel and curved member the support-wheelsspaced apart to form a two-point-support wheel base for thefassembly and means tangent to the lower periphport-wheels travelable upon the lower fold eries of the support-wheels to control the of the track intermediate of the wheel and flexure of the chain between the points of curved member the support-wheels spaced support. apart to form a two-point-support wheel 5 9. In a track-assembly for vehicles, an base for the assembly and means tangent to 15 endless chain-track, a wheel near one end, the lower peripheriesof the support-wheels an oppositely disposed curved member 00- to control the flexure of thechain between acting with the wheel to maintain the upper the points of support. and lower folds of the chain-track in the r 1 10 same plane of travel, spring-controlled sup- WILLIAM HVSMYTH. 

